Re: [9fans] PDP11 (Was: Re: what heavy negativity!)

["Digby R.S. Tarvin" <digbyt42@gmail.com>]

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A native Inferno port would certainly be a lot easier, but I think you
might be a bit pessimistic about would can fit into a 64K address space
machine. The 11/70 certainly managed to run a very respectable V7 Unix
supporting 20-30 simultaneous active users in its day, and I wouldn't have
thought plan 9  arriving about a decade later, would have been hugely
bigger than V7 Unix.
I recall a demo of Plan9 (I think it also included the source) being given
by Rob Pike at UNSW which he carried on a 1.44Mb floppy disc. By its open
source release in 2002 the distribution was 65MB

The smallest Linux system I have used recently had 256K RAM and 512K flash.
A rather stripped down busybox based system, but it did include a full
TCP/IP stack and a web server. Thats comparable to a PDP11 except for the
limitation on the largest individual process.

Bear in mind that 16 bit executables are smaller, and whilst the 11/70 had
a 64Kb address space, physical memory could be somewhat larger, and an
individual process could have 128K of memory is using separate instruction
and data space.

I am used to thinking of Plan9 as very compact, but I havn't really looked
to see if it has grown much since the 80s, and perhaps it is only next to
the astronomical expansion of other systems that it still looks small. It
would be an interesting exercise to find out.

It would be an interesting thing to try, if only to get a better feel for
how compact Plan9 actually is ...

DigbyT

On Mon, 8 Oct 2018 at 14:38, Lucio De Re <lucio.dere@gmail.com> wrote:

> On 10/8/18, Digby R.S. Tarvin <digbyt42@gmail.com> wrote:
> >
> > So the question is... is plan9 still lean and mean enough to fit onto a
> > machine with a 64K address space? Doing a port would certainly provide
> > plenty of opportunity to tinker with the lights and switches on front
> > panel, and if it the port was initially limited to being a CPU server,
> > there would be no need to worry about displays and mass storage.... just
> > the compiler back end and low level kernel support.
> >
> You really must be thinking of Inferno, native, running in a host with
> 1MiB of memory. 64KiB isn't enough for anything other than maybe CPM.
> Even MPM won't cut it, I don't think.
>
> Lucio.
>

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